Revert of Don't reset scroll position of contents on every ScrollView layout.

ash/common/system/tray/tray_details_view.cc

Index: ash/common/system/tray/tray_details_view.cc
diff --git a/ash/common/system/tray/tray_details_view.cc b/ash/common/system/tray/tray_details_view.cc
index cf0650f411206f4425e7e5705a77072ff11d20de..8baa6615f4654386cee81e2a3c9d2e71a6352a3a 100644
--- a/ash/common/system/tray/tray_details_view.cc
+++ b/ash/common/system/tray/tray_details_view.cc
@@ -484,10 +484,9 @@
     views::View::Layout();
     if (scroller_ && !scroller_->is_bounded())
       scroller_->ClipHeightTo(0, scroller_->height());
-    return;
-  }
-
-  if (bounds().IsEmpty()) {
+  }
+
+  if (UseMd() || bounds().IsEmpty()) {
     views::View::Layout();
     return;
   }